Planetary carriers such as the one used for automatic transmission are manufactured by powder metallurgy for reduction of the manufacturing costs.
In powder metallurgy, planetary carriers are manufactured by sintering a first compact and a second compact, which are made of powder, in the state where the first and second compacts are superposed one on the other and concurrently joining the first and second compacts together by soldering.
A pillar stands erect on a surface of a plate-shaped base of the second compact. The second compact is placed below and the first compact is mounted at the tip of the pillar directed upward. The second compact and the first compact are joined together after joint surfaces of the pillar and the first compact are caused to be impregnated with solder.
This method for manufacturing planetary carriers is described in, for example, PTLs 1 and 2.